Brushhead for a power toothbrush with a two position coupling assembly

ABSTRACT

The replaceable brushhead, used for a power toothbrush, includes a neck portion (22) having a hollow part located at a proximal end thereof. The brushhead assembly includes a bristle portion (18) at a distal end of the neck portion. A connecting assembly (20) is positioned within the hollow portion of the neck, the connecting assembly having two distinct, mechanically stable, positions. In the first position, the connecting assembly has a first physical arrangement in which the brushhead assembly is conveniently removable or insertable onto an output shaft (16) from a handle portion of the power toothbrush. In the second position, the connecting assembly has a second physical arrangement, in which a portion of the connecting assembly makes physical contact with the output shaft such that the force or torque produced by the output shaft in operation is transferred to the brushhead assembly for movement thereof.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This Application is a divisional application of U.S. application Ser.No. 14/353,663, filed Apr. 23, 2014 (now issued U.S. Pat. No.9,597,169), which is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/IB2012/005689, filed on Oct.18, 2012, which claims the benefit of U.S. Provisional PatentApplication No. 61/551,035, filed on Oct. 25, 2011. These applicationsare hereby incorporated by reference herein.

This invention relates generally to a brushhead assembly for a powertoothbrush, wherein the brushhead assembly includes a connectionarrangement designed for two-position operation; in one position forinsertion and removal of the brushhead relative to the driveshaft fromthe toothbrush motor and in the other position for engagement with thedriveshaft for operation of the toothbrush.

The brushhead portion of a power toothbrush typically has a much shorteruseful life than the remainder of the toothbrush, i.e. the handle, whichincludes generally the drive, control and power assemblies of theappliance. The brushhead must be both convenient to remove and insertonto the driveshaft of the toothbrush, but also must be able to reliablytransfer the force of the driveshaft to the brushhead with a minimumloss of motion. A large number of different structural arrangements havebeen used to accomplish these two different and somewhat conflictingrequirements. In most cases, the brushhead has a single configurationwhich accomplishes both results, i.e. it has a tight enough fit toprovide the required force transfer but which can be pulled on and offthe drive member (driveshaft) with a reasonable amount of force exertedby a typical user. What is presently disclosed is a brushhead which hasa connecting arrangement with two different stable physical positions,which facilitates the separate requirements of convenientinsertion/removal and reliable transfer of force from the drive member.

Accordingly, the replaceable brushhead assembly for a power toothbrushhaving a handle portion and an output shaft for driving the brushheaddisclosed herein comprises a neck portion having a hollow part at aproximal end thereof; a bristle portion at a distal end of the neckportion; and a connecting assembly positioned or positionable within thehollow part of the neck portion, the connecting assembly having twodistinct, mechanically stable, different positions, including a firstposition in which the connecting assembly has a first physicalarrangement permitting the brushhead assembly to be readily removablefrom or insertable onto the output shaft, and a second position in whichthe connecting assembly has a second physical arrangement in which theconnecting assembly makes physical contact with the output shaft and isconnected to the neck portion such that the output shaft force istransferred to the brushhead assembly in operation of the powertoothbrush.

FIG. 1 is an exploded view of a power toothbrush.

FIGS. 2A-2C are several views of a portion of one embodiment of the twoposition brushhead disclosed herein.

FIG. 3 is an isometric view of the drive member (shaft) configuration ofthe first embodiment.

FIGS. 4A-4C are several views of a coupling assembly portion of thefirst embodiment.

FIGS. 5A and 5B show the two operating positions (open and closed) ofthe first embodiment.

FIGS. 6A-6C are various views of the structure and operation of a secondembodiment of the two-position brushhead.

FIGS. 7A-7C are various views of the structure and operation of anotherembodiment of the two-position brushhead.

FIG. 1 is an exploded view of a power toothbrush, shown generally at 10.The power toothbrush 10 includes a handle portion 12 and a drive systemand a control system shown generally as a unit at 14 which areconventional in structure and operation and which can take variousforms, for driving an drive/output shaft 16 with a desired motion. Oneexample is an oscillatory motion with a frequency of approximately 260Hz and an amplitude of approximately 10°. It should be understood thatthis described action is one example only and can be varied. The powertoothbrush 10 also includes a removable brushhead assembly 17 whichincludes a set of bristles 18 at a distal end thereof. The brushheadassembly 17 is structured to be removable from the output shaft 16 whenit is due for replacement. A new brushhead assembly is then insertedonto the output shaft 16 for continued operation of the toothbrush.

The present invention, as disclosed and claimed herein, is directedtoward a connecting assembly 20 which fits within a neck portion 22 ofthe brushhead assembly 17. The connecting assembly 20 is configured andadapted to operate between two positions. In one position, a brushheadis conveniently removable from the output shaft or positionable on theoutput shaft, while in the second position, the brushhead assembly isfirmly attached or fixed to the output shaft such that the force ortorque produced by the output shaft is transferred to the brushheadassembly, preferably without any lost motion.

The subject of this application is the brushhead assembly with theconnecting assembly therein. The connecting assembly can take variousarrangements, including the embodiments shown herein. FIGS. 2A-2C, 3,4A-4C and 5A-5B show the structure and operation of a first embodiment.FIGS. 2A-2C show one part/member of the first embodiment of theconnecting assembly. Member 26 is in the form of a ring which is fixedlyattached to an inner surface of neck portion 22 of the brushhead, whichis hollow for at least a lower part of its length from its proximal end24. The outer surface 28 of ring member 26 mates against and hasapproximately the same dimension as the inner surface of neck 22. In theembodiment shown, the ring has a height of approximately 6 mm and awidth (thickness) of approximately 2 mm over most of its circumference.One portion 32 of inner surface 30 of ring member 26 is flat and has asmall element 34 which extends inwardly of the ring a short distance,terminating at a free end surface 35, which extends directly downwardlyfor a part of the height of the ring member and then angles inwardly atsurface 37 over the remaining portion thereof, as shown in FIG. 2C. Inthe embodiment shown, this angle is approximately 60°. FIG. 3 showsanother part of the first embodiment, namely a notched output shaft 39from the handle. The output shaft includes a flat upper surface 40. Anotch or cutout section 42 begins approximately 6 mm down from surface40 and extends inwardly approximately one-half the diameter of theoutput shaft. The notch 42 extends downwardly of the shaft a distance ofapproximately 10 mm.

FIGS. 4A-4C show another part of the first embodiment, namely, acoupling member 50 part of the connecting assembly of the firstembodiment. The coupling member fits also within the lower portion ofthe neck 22 of the brushhead, and is hollow, as shown most clearly inFIG. 4C, to receive output shaft 39 (FIG. 3) from the handle. Thecoupling member is generally cylindrical and includes a movable flapportion 56 which extends downwardly from the upper surface 52 the entirelength of the coupling member, as shown most clearly in FIG. 4B. Themovable portion 56 is connected to the upper surface of the couplingmember by a hinge-like portion 57 which permits the movable portion tobe moved inwardly of the coupling member. The movable portion includes aflat upper portion 58 which extends downwardly to an outwardly anddownwardly angled portion 59 which, in the embodiment shown, has anangle of approximately 60°, which mates with the angled portion 37 ofring member 26 when the connecting assembly is in its first position.The angled portion 59 extends to another vertical flat portion 60 whichends in a small horizontally outwardly extending lip 62 which in thefirst position of the brushhead contacts the inner surface of the neckof the brushhead below ring 26.

FIGS. 5A and 5B show the operation of the first embodiment. In the firstposition, shown in FIG. 5A, also referred to as an open position, abrushhead 63 (only a lower part is shown), along with the couplingmember, is conveniently removable from the output shaft 39, and is alsoreadily insertable onto the output shaft. In this first position, angledportion 37 of ring 26 is adjacent the angled portion 59 of the movableportion of the coupling member, with the movable portion in itsoutermost, i.e. rest, position, permitting the entire brushhead to beconveniently removed from the output shaft 39. When the output shaft 39is then further pushed into the brushhead assembly, or vice versa, theangled part of the ring member moves down the angled surface 59 of theremovable portion of the coupling member, forcing the movable portioninwardly against flat portion 64 of the output shaft. This movement ofthe output shaft into the brushhead assembly continues until thecoupling member reaches the position shown in FIG. 5B, where the loweredge 67A of the ring member contacts the lip 62 of the movable portionof the coupling member. At this point, the inner surface 65 of themovable portion 56 is forced against the flat portion of the outputshaft, in which position the force of the moving output shaft istransferred to the brushhead, as shown in FIG. 5B. When the brushhead isto be removed, the brushhead is simply pulled away from the handle,allowing the movable portion of the coupling assembly to return to itsrest position, as shown in FIG. 5A, which allows the brushhead assemblyto be easily removed.

FIGS. 6A-6C show a second embodiment of a connecting assembly for atwo-position brushhead assembly, the connecting assembly beingpositioned in the lower portion of the neck of the brushhead assembly.FIG. 6A shows a connecting assembly 61 which includes a top portion 66having a length 66A and spaced end portions 67 and 68 which extenddownwardly from top portion 66 at an angle A of 90° relative to the topportion. The top portion is connected to the end portions by two pins 69and 70. The connecting member is arranged and constructed so that topportion 66 flexes between two positions, a concave position in which thetop portion bends inwardly (FIG. 6B), and a convex position in which thetop portion bends outwardly (FIG. 6C). The connecting member can be madefrom a flexing plastic or metal. FIG. 6B shows the connecting member inits first, convex, position, in which position the distance between thetwo pins 69 and 70 is 66B, which is less than 66A. The top portion 66fits within the opening of neck portion 72 of the brushhead assemblywhen the top portion is in its convex position in which distance 66Bbetween the pins 69 and 70 is just wide enough to fit in the opening inthe neck portion. The dimensions of the top portion will vary dependingon the size of the neck opening. In one example, the top portion is 10mm long and 4 mm wide. When connecting member 61 is inserted into theneck portion (in its FIG. 6B position), the two pins 69 and 70 arecaptured in mating slots 73, 73A in the inside surface of neck 72. Theneck 72 extends to the remainder of the brushhead assembly (not shown).The angle between the top portion and each of the two end portions isstill 90°. The brushhead assembly is provided for use with the insertedconnecting member in the position of FIG. 6B.

When the brushhead assembly is to be moved onto the handle, the outputshaft 74 from handle 75 is moved against the undersurface 76 of the topportion 66. The two end portions move toward each other and the topportion snaps into its second, convex position, as shown in FIG. 6C. Inthis position, there remains a 90° angle between the top portion andeach of the two end portions, respectively. As the output shaft movesagainst the under surface of the top portion, the top portion snaps intoits second position. The distal ends 78, 80 of the end portions havesmall protuberances 82 and 84, which move into detents 86 and 88 in theoutput shaft. In this position, the brushhead is firmly fixed to theoutput shaft and the force of the movement of the output shaft istransferred to the brushhead assembly. When the brushhead assembly is tobe removed, the output shaft is pulled slightly away from the brushhead,forcing the two end members outwardly, so that the top portion of theconnecting assembly snaps back into its concave position. The brushheadcan then be conveniently and easily removed from the output shaft.

FIGS. 7A-7C show a further embodiment involving a spring arrangement ina connecting assembly which fits within the lower part of the neck of abrushhead assembly. The connecting assembly, shown generally at 90,includes a cylindrical upper member 92 having a diameter which fitswithin the neck of the brushhead. The upper member 92 includes a topring-like portion 94 and two depending leg members 96 and 98 (FIG. 7B).The upper member is connected to an inner portion of the neck of thebrushhead by a vertical spring 100. The connecting assembly includes acoupling assembly which includes upper and lower flat plate portions102, 104, each of which has a central opening which allows an outputshaft 107 from the handle of the toothbrush to extend therethrough, asshown in FIG. 7C. The upper plate 102 contacts the two leg members 96and 98 of the upper member, while the lower plate is configured tocontact the inner surface of the hollow neck portion of the brushhead.Positioned between the two plate portions 102 and 104 are two springedelements 106 and 108, which in one position are bowed outwardly(concave), as shown in FIG. 7A, when the brushhead assembly is apartfrom the output shaft 107. As the output shaft moves into the couplingassembly, the two springed elements snap into their second position, asshown in FIG. 7C. The springed elements including protruding portions110, 112 which extend toward each other from the inner surfaces of thespringed elements and contact detents 114, 116 in the opposite sides ofthe output shaft. In this position of the connecting assembly, thebrushhead is held firmly against the output shaft, such that the forceproduced by the output shaft is transferred to the brushhead.

Two springs 118 and 120 connect upper plate 102 to the upper member 92so that as the output shaft is pulled out of the brushhead, when thebrushhead is to be replaced, the two spring members 106 and 108 snapback into their first position, and the coupling member remains attachedto the connecting assembly and within the brushhead, i.e. the couplingmember does not pull away from the brushhead.

Various embodiments have been shown and described which define abrushhead having a connecting assembly therein which moves between twopositions, as the output shaft (driveshaft) from the handle is insertedinto the brushhead. In one position, the connecting assembly is arrangedand configured so as to conveniently permit the brushhead to be removedfrom the output shaft, and also to permit a brushhead to be insertedonto the output shaft. In a second position, the coupling portion of theconnecting assembly comes into mechanical contact with the output shaftin such a manner that the torque force produced by the output shaft istransferred to the brushhead, with little or no lost motion.

Although a preferred embodiment of the invention has been disclosed herefor the purposes of illustration, it should be understood that variouschanges, modifications and substitutions may be incorporated in theembodiment without departing from the spirit of the invention, which isdefined by the claims which follow.

The invention claimed is:
 1. A replaceable brushhead assembly for apower toothbrush having a handle portion and an output shaft for drivingthe brushhead, comprising: a neck portion having a hollow part at aproximal end thereof; a bristle portion at a distal end of the neckportion; and a connecting assembly positionable within the hollow partof the neck portion, the connecting assembly having at least twodistinct, different physical positions, including a first distinctphysical position, and a second distinct physical position wherein theconnecting assembly snaps between the first and second distinct physicalpositions, depending upon the relative positions of the connectingassembly, the output shaft and the neck of the brushhead assembly; andwherein the connecting assembly comprises (i) a spring part (ii) twolegs which extend downwardly from opposing ends of the spring part,having protuberances at the lower ends thereof which mate with detentson the output shaft in response to the connecting assembly being in itssecond distinct physical position.
 2. The brushhead assembly of claim 1,wherein the spring part is disposed at an angle of 90° with respect toeach of the two legs in response to the connecting assembly being in itsfirst or second distinct physical position.